An audio, video, navigation (AVN) system is a vehicle multimedia system in which an audio system, a video system, and a navigation system are integrated in the form of one unit. By virtue of development of the AVN system, a user can enjoy convenience in manipulating various multimedia apparatuses and can effectively use an internal space of a vehicle.
Recently introduced vehicles have various convenience systems for facilitating safe driving of a driver. When a dangerous situation is predicted, the convenience system audibly or visually warns a driver of the dangerous situation and, when a dangerous situation occurs, the convenience system automatically copes with the situation so as to facilitate safe driving of a driver.
When a car accident occurs, the car automatically or manually transmits information on a current location of the car, a gyro sensor value, whether an air bag is deployed, etc. to an emergency or rescue center and a driver actually speaks over a telephone with an adviser of the center using a speaker or microphone in the vehicle so as to recognize a current accident situation and to rapidly cope with the accident. This service is referred to as an SOS service.
However, an exterior amplifier, a digital voice output port (e.g., Sony/Philips digital interface (SPDIF)), media oriented systems transport (MOST), a controller area network (CAN) communication line, etc. for telephone conversation as well as a speaker can be damaged due to a car accident. Accordingly, the speaker in the vehicle cannot be operated during telephone conversation with an adviser who provides the SOS service, but the call-connected adviser cannot check an actual sound output state of the vehicle and normal telephone conversation is frequently impossible.